In the refining of metal, such as silicon metal, an electrode is brought into contact with ore to provide electric current to heat the ore to bring about a refining reaction. During this process, the electrode is consumed, and it is necessary to advance the electrode to maintain its contact with the ore.
A known type of electrode for this purpose is a self-baking electrode. These electrodes utilize an electrode paste which is subjected to elevated temperatures (preferably approximately 400.degree. C.) to "bake" the paste into a somewhat rigid electrode. The electrical resistivity of the baked electrode paste is lower than that of the unbaked paste so that the baked electrode conducts sufficient current to heat the ore without significant energy loss.
Known self-baking electrodes are shown in U.S. Pat. Nos. 1,442,031 (Soderberg); 1,640,735 (Soderberg); 3,524,004 (Van Nostran et al.); and 4,527,329 (Bruff et al.).
Other known self-baking electrodes utilize an elongate casing having support structure, such as radially-directed fins, a cable having transverse bars thereon, or an elongate cylinder of graphite for engaging the electrode paste and the baked electrode to provide support. During the refining operation, the entire structure is allowed to advance downwardly into the furnace. Support elements are located remote from the furnace and generally engage a casing which is advanced into the furnace and is consumed along with the electrode. The electrode paste is baked by passage of electrical current through it, and the current is provided by shoes in contact with the electrode at a location closer to the furnace than that of the support elements.